1. Field of the Invention
The present invention relates to a High Density Pluggable connector. More particularly, to a High Density electrical and optical connector that has a bi-directional connection to the socket.
2. Background of the Related Art
Electronic systems are often assembled from one or more printed circuit boards (PCBs) which contain a wide variety of electronic components. These boards are often referred to as “daughter cards” which connect to a common backplane or “mother board” which also contains various connectors and circuitry. The daughter cards usually include one or more connectors that allow for communication with the backplane or an opposing daughter card when configured in a midplane scenario. A midplane is generally nothing more than a card sandwiched between two opposing daughter cards. The cards can be parallel or perpendicular depending upon the application. An example of such a system is shown in U.S. Pat. No. 4,686,607 to Johnson.
In order for the cards to communicate, the electrical signals referred to as “traces” are routed from one daughter card to another and travel through the backplane as well. These traces are produced using readily known photolithographic manufacturing techniques which produce embedded copper lines that carry the signals along a cards matrix. The electrical connectors that enable these cards to talk with each other are mounted to pads or vias that contact the traces in the matrix and route the appropriate signals. Some examples of connectors can be seen in U.S. Pat. Nos. 6,409,543; 6,506,076; 6,592,381, and 6,602,095, which are hereby incorporated as reference.
When there is a need for signals to be carried at higher speeds or greater distances, fiber optic connectors are typically employed. Fiber optic connectors are shown, for instance, in U.S. Pat. No. 6,776,645 and U.S. Patent Application Publication No. 2006/0002659. These connectors can be mounted on either end of the PCB. The side opposing the backplane or midplane is generally referred to as the front panel. The front panel is typically the outside of the system that the user sees and has access to. Commercially standard connectors have been employed in conjunction with pluggable transceiver technologies. The pluggable transceivers literally plug through an opening in the front panel which is typically aluminum and attach directly to a pre-affixed connector within a shielded cage on the daughter card. When the devices are fully coupled, they typically latch in place and await connection to a second fiber optic transmission line, which is plugged directly into the device such as an industry standard optical connector as the ST (Straight Tip) or LC (Lucent Connector). These optical connectors typically house a ferrule that holds a single-fiber or a multi-fiber optical ribbon. A parallel (multi-fiber) ferrule simply allows for a signal greater carrying capacity in the space available. The same sort of devices can be used on the backplane side, but generally involve much more complicated mechanical designs to implement latching that is automatic and blind to the user, as shown in U.S. Pat. No. 6,762,941 and Published No. 2006/0002659.
It is often desirable for all these systems to be as compact and dense as possible. Thus, when connectors shrink in size, their latching mechanisms and other components must be reduced in size as well. This miniaturization of components creates a challenge when designing a connector that is robust, reliable and easy to use.
The present design addresses many of these challenges while simultaneously implementing many new and innovative features. In addition it attempts to address the present needs of the equipment manufacturers who are desirous of employing front panel parallel optical transceiver technologies in their systems in an effort to drive toward miniaturization, reduced power and lower heat formation, while improving the shielding for higher speed applications.
Though these devices may differ slightly from manufacturer to manufacturer, they are generally the same. One such module is shown in U.S. Publication No. 2007/0013017. Each module includes opto-electronics, such as surface emitting 850-nm VCSELs (Vertical Cavity Surface Emitting Laser) and detectors. The modules also include interface electronics, such as driver and receiver circuits, along with an interface to a fiber ribbon consisting of multiple glass fibers, housed in a connector. These connectors can transfer data over different channels in parallel, offering point-to-point communication with bandwidth and distance achievements far exceeding copper capabilities.
One drawback of any of the existing front panel solution, whether electrical or optical, is the fact that the connections require a right angle interconnect to transition from the plugging direction to the parallel surface of the daughtercard, which is not accessible to the user. In this manner, the connector is directly pressed onto the (optical or electrical) contacts of the PCB or faceplate in a single motion and in a direction perpendicular to faceplate, such as shown by at least the Johnson and Roth '858 patents above. By locating the contacts on the front surface, a greater surface area of the faceplate or PCB is required as the number of contacts is increased for a particular application. Consequently, the number of connections that can be made is limited by the amount of front surface that is available on the PCB or faceplate. In other words, as signal count increases so does the width of the connector which is not desirable from a system architecture point of view. Maximizing front panel density is often crucial since lower density cards typically mean that more system level cards are required to do the same job.
This also means that the right angle connector at higher electrical speeds is far more difficult to implement and design due to the many nested signal integrity problems that are likely to occur. As the signal counts and speeds increase, the trace routings that come out of the right angle connector also become more challenging to implement. In the proposed approach both of these problems are overcome by purely changing the position of the electrical interface by a 90 degree rotation in relation to the conventional approaches, thereby allowing the connector to grow in length vs. width while providing for maximum flexibility in routing the traces on the circuit card and simplifying the overall right angle connector design.